In my last post I alluded to the fact that big changes to the antenna situation here at AA7EE could happen soon. I’ve been painfully aware that my antenna just ain’t cuttin’ it. It’s not the antenna (a Buddistick vertical, and more recently a 65-70 foot longwire as well) it’s the fact that it’s mounted on my balcony with the feedpoint at 20 feet above ground, giving me a reasonable take-off to the west, a bad take-off to the north, average take-off to the south and absolutely abominable take-off to the east, which as I’m in the San Francisco Bay area, is most of the rest of the country.
Today, the owner of my apartment building indicated that he would be open to my placing a 31 foot vertical on the roof of the building provided that a) it doesn’t break any local ordinances and b) he’s satisfied that it isn’t going to fall over and hurt or annoy anyone. Just as I was looking around for a new place to live, I get the carrot from him that might tempt me to stay! To help explain the situation, here’s a cross-section of my apartment building, showing my apartment and the location of the current antenna on the first floor, as well as the proposed location of the new antenna. This new antenna, as well being about 35 feet higher than the existing one, would give me a pretty good take-off in all directions – a major breakthrough:
The antenna I’m considering is an S9V 31 foot vertical with a bunch of radials lying on the roof and an ATU located at the base of the antenna with 50 ohm feed going back to the “shack”. I’m pretty excited about this as I think it will be a great improvement over the current antenna location. Tomorrow morning, I’m grabbing a ladder and heading out onto the roof to do a bit of research. At the very worst, I’ll get a great view of the City of Oakland, but I think this is going to be good.
If anyone has alternative antenna suggestions, I am very open.
Dave,
I think that’s an excellent plan. With a vertical mounted there, you should get a nice, low takeoff angle all around. If you need to work closer in, you could get some more parts to make your Buddistick into a Buddipole dipole. Have you seen the March 2010 QST? There’s a nice article about the effects of radials on vertical antennas. I don’t know if it’s feasible or not, but I wonder if you can get your radials elevated a foot or so?
I’m heading to HRO to get that QST today – perhaps it’s time for me to come back to the League and join up again. Thanks for the tip Jason. You’ve got me thinking that, as the antenna will be on a rooftop and not close to ground, it wouldn’t take much elevation from the surface of the roof for me to be able to use one radial instead of a whole bunch – with an ATU at the base of the antenna it would then be more of a dipole (like the Buddistick).
Thanks for the tip on the article and for putting these thoughts into my head!
Dave, I think the improvement will be phenomenal over what you currently have. I notice the antenna you linked also has an 80m coil available as an option – guess you’ll need that for the FT80…
Even though I’m happy with my 10-80 dipole, I’ve periodically pondered putting up an antenna like this vertical just to have an alternate for those times when the dipole may not be appropriate. From what I’ve read, it should outperform the dipole on some 40m DX paths.
One of the conclusions in the QST article Jason mentioned is that if you have to choose between a few long radials or a higher numer of short radials, choose the latter.
And while you’re at HRO, browse through the chapter on verticals in ON4UN’s Lowband DXing book – lot’s of good info there that may apply to your situation.